The present invention relates to a dental instrument for removing caries attacked dentine.
In traditional caries treatment the attacked tooth substance is removed mechanically by means of a dentist's drill or a cutting excavator. Such a caries treatment is often a painful and unpleasant experience for the patient. Some of the patients feel so uncomfortable with the treatment that they wait far too long before they visit a dentist, which means that it is often too late to save the caries attacked teeth. Extraction of the teeth is then the only treatment method that is left.
However, there are other methods which are based on a chemical-mechanical treatment for the removal of the caries attacked substance. A method of this type is described in SE 460258. According to this method a two-component liquid is mixed and then immediately applied on the caries site. Functioning in a biological way, the liquid makes the caries attacked substance soft without causing any damage to the tooth or the soft tissue. After 10-15 seconds the dentist can start removing the carious substance by means of an excavator. The excavating operation continues until all caries substance has been removed. Then the cavity is filled with a suitable material.
According to the above patent the two-component liquid consists of a sodium hypochlorite component and a nitrogen-containing component. The nitrogen-containing component consists of three nitrogen-containing compounds with different charge states; one neutral, one with a negative net charge and one with a positive net charge.
Unlike conventional mechanical caries treatment methods the biological treatment method is usually not at all painful. Neither does it require any investments in expensive equipments. It only requires an excavator instrument to remove softened carious dentine material.
Traditional excavator instruments, however, are not suitable for this purpose as they are cutting tools and not made for just scraping away already softened dentine material from different types of cavities and therefore could damage healthy dentine.
The specific instruments that have been previously used in connection with the chemical-mechanical treatment method are mainly related to the distribution of the liquid solution for softening the carious dentine material. An apparatus for supplying such a liquid is previously disclosed in U.S. Pat. No. 4,793,807. The apparatus comprises an applicator 34 having a tubular implement through which the solution is applied on the caries site. According to the patent specification the tubular implement has a spoon-shaped tip end 188 which can be used for removing by scraping carious dentine material. However, such an instrument with an applicator integrated scraping implement requires expensive equipment and is not suitable for practical, frequent, manual use. Furthermore, the tip ends are not designed for all kind of cavities.